Synthese RedOx-responsiver Partikel via starved-feed Emulsionspolymerisation zur Herstellung funktionaler Nanoarchitekturen

Im Fokus dieser Arbeit stand die Entwicklung neuartiger funktionaler Nanoarchitekturen für zukünftige Anwendungen im Bereich von optischen Sensoren und Sicherheitsmerkmalen, der elektrochemischen Adsorption sowie der selektiven Anreicherung von Kohlenstoffdioxid. Grundlage hierfür bildet die Integration von RedOx- und pH-responsiven Komponenten innerhalb der Architektur von monodispersen Kern-Zwischenschicht-Schale Partikeln (engl.: core interlayer shell particles, CIS) auf der Nanometerskala. Die immense Vielfalt zeigte sich bereits in der Diversität der adressierbaren Einheiten, welche angefangen von Ferrocen basierten Monomeren, über Carbonyl haltige Verbindungen bis hin zu organischen Farbstoff Molekülen reichte. Für die Synthese von maßgeschneiderten Nanopartikeln einheitlicher Größe und definierter Zusammensetzung stellte die starved-feed Emulsionspolymerisation die Methode der Wahl dar, sowohl rein organische als auch hybride Nanopartikel zu synthetisieren. Die Integration der entsprechenden Stimuli-responsiven Komponente erfolgte in Abhängigkeit der chemischen Eigenschaften über verschiedene Routen wie der direkten (Co-) Polymerisation, der Postmodifizierung sowie verfahrenstechnischen Ansätzen auf Basis der Extrusion. Darüber hinaus konnte die Selbstanordnung von monodispersen Nanopartikeln durch die Einwirkung von Scherkräften zur Herstellung von freistehenden kolloidalen Kristallen in Form von sogenannten Opal- und Inversopalfilmen ausgenutzt werden. Während dem Prozess ordnen sich die Kern-Partikel in einer Polymermatrix, bestehend aus dem Schalenmaterial, zu einem dichtest-gepackten Kristallgitter an. Bei einem ausreichenden Brechungsindexkontrast zwischen dem Kern- und dem Schalenmaterial kommt es durch die spezifische Wechselwirkung von sichtbarem Licht und den einzelnen Netzebenen der hochgeordneten Nanostruktur, gemäß der BRAGG-Gleichung, zur Entstehung einer ausgeprägten Strukturfarbe. Somit war es erfolgreich möglich, durch die Integration von pH- und RedOx responsiven Komponenten innerhalb des Matrixmaterials schaltbare Opal- und Inversopalfilme herzustellen, deren optische Eigenschaften durch verschiedene äußere Reize wie mechanischem Stress, dem Anlegen einer elektrischen Spannung oder durch die Behandlung mit chemischen Oxidations- und Reduktionsmitteln effizient und reversibel geschaltet werden konnten. Des Weiteren wurde die Selbstanordnung von 2-Aminoanthrachinon-haltigen Nanopartikeln zur Applikation auf einem leitfähigen Carbonvlies genutzt und die erhaltenen Kompositmaterialien in einer Electro-Swing-Adsorption (ESA) zur selektiven Anreicherung von Kohlenstoffdioxid analysiert. Zudem setzte sich die vorliegende Arbeit neben der Einführung von pH- und RedOx-responsiven Funktionalitäten mit der Synthese und Charakterisierung eines neuartigen Ferrocen-haltigen Polymers, namentlich Polyferrocenylmethylen (PFM), auseinander, welches im Vergleich zu seinem Analogon Polyferrocenylsilan (PFS) nicht über die von MANNERS et al. postulierte Ring-öffnende Polymerisation von gestreckten [1]Ferrocenophanen zugänglich ist. Die Charakterisierung der neuartigen Verbindungen erfolgte über gängige polymeranalytische Methoden sowie der Cyclovoltammetrie, um detaillierte Erkenntnisse über die RedOx-responsiven Eigenschaften zu erhalten. Vor dem wissenschaftlichen Hintergrund, dass Metallopolymere als präkeramische Materialien für diverse Anwendungen interessant sind, wurden die thermisch behandelten Überstände final mithilfe der Röntgenstrukturanalyse untersucht

Dye-Loaded Mechanochromic and pH-Responsive Elastomeric Opal Films

In this work, the preparation and fabrication of elastomeric opal films revealing reversible mechanochromic and pH-responsive features are reported. The core-interlayer-shell (CIS) particles are synthesized via stepwise emulsion polymerization leading to hard core (polystyrene), crosslinked interlayer (poly(methyl methacrylate-co-allyl methacrylate), and soft poly(ethyl acrylate-co-butyl acrylate-co-(2-hydroxyethyl) methacrylate) shell particles featuring a size of 294.9 ± 14.8 nm. This particle architecture enables the application of the melt-shear organization technique leading to elastomeric opal films with orange, respectively, green brilliant reflection colors dependent on the angle of view. Moreover, the hydroxyl moieties as part of the particle shell are advantageously used for subsequent thermally induced crosslinking reactions enabling the preparation of reversibly tunable mechanochromic structural colors based on Bragg's law of diffraction. Additionally, the CIS particles can be loaded upon extrusion or chemically by a postfunctionalization strategy with organic dyes implying pH-responsive features. This convenient protocol for preparing multi-responsive, reversibly stretch-tunable opal films is expected to enable a new material family for anti-counterfeiting applications based on external triggers

Dye-Loaded Mechanochromic and pH-Responsive Elastomeric Opal Films

In this work, the preparation and fabrication of elastomeric opal films revealing reversible mechanochromic and pH-responsive features are reported. The core–interlayer–shell (CIS) particles are synthesized via stepwise emulsion polymerization leading to hard core (polystyrene), crosslinked interlayer (poly(methyl methacrylate-co-allyl methacrylate), and soft poly(ethyl acrylate-co-butyl acrylate-co-(2-hydroxyethyl) methacrylate) shell particles featuring a size of 294.9 ± 14.8 nm. This particle architecture enables the application of the melt-shear organization technique leading to elastomeric opal films with orange, respectively, green brilliant reflection colors dependent on the angle of view. Moreover, the hydroxyl moieties as part of the particle shell are advantageously used for subsequent thermally induced crosslinking reactions enabling the preparation of reversibly tunable mechanochromic structural colors based on Bragg's law of diffraction. Additionally, the CIS particles can be loaded upon extrusion or chemically by a postfunctionalization strategy with organic dyes implying pH-responsive features. This convenient protocol for preparing multi-responsive, reversibly stretch-tunable opal films is expected to enable a new material family for anti-counterfeiting applications based on external triggers

Rings and Chains: Synthesis and Characterization of Polyferrocenylmethylene

The synthesis and characterization of polyferrocenylmethylene (PFM) starting from dilithium 2,2-bis(cyclopentadienide)propane and a Me2C[1]magnesocenophane is reported. Molecular weights of up to Mw = 11 700 g mol–1 featuring a dispersity, Ð, of 1.40 can be achieved. The material is studied by different methods comprising nuclear magnetic resonance (NMR) spectroscopy, matrix-assisted laser desorption/ionization time of flight (MALDI-ToF) mass spectrometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) measurements elucidating the molecular structure and thermal properties of these novel polymers. Moreover, cyclic voltammetry (CV) reveals quasi-reversible oxidation and reduction behavior and communication between the iron centers. Also, the crystal structure of a related cyclic hexamer is presented

Factors predictive of successful retention in care among HIV-infected men in a universal test-and-treat setting in Uganda and Kenya: A mixed methods analysis.

BackgroundPrevious research indicates clinical outcomes among HIV-infected men in sub-Saharan Africa are sub-optimal. The SEARCH test and treat trial (NCT01864603) intervention included antiretroviral care delivery designed to address known barriers to HIV-care among men by decreasing clinic visit frequency and providing flexible, patient-centered care with retention support. We sought to understand facilitators and barriers to retention in care in this universal treatment setting through quantitative and qualitative data analysis.MethodsWe used a convergent mixed methods study design to evaluate retention in HIV care among adults (age > = 15) during the first year of the SEARCH (NCT01864603) test and treat trial. Cox proportional hazards regression was used to evaluate predictors of retention in care. Longitudinal qualitative data from n = 190 in-depth interviews with HIV-positive individuals and health care providers were analyzed to identify facilitators and barriers to HIV care engagement.ResultsThere were 1,863 men and 3,820 women who linked to care following baseline testing. Retention in care was 89.7% (95% CI 87.0-91.8%) among men and 89.0% (86.8-90.9%) among women at one year. In both men and women older age was associated with higher rates of retention in care at one year. Additionally, among men higher CD4+ at ART initiation and decreased time between testing and ART initiation was associated with higher rates of retention. Maintaining physical health, a patient-centered treatment environment, supportive partnerships, few negative consequences to disclosure, and the ability to seek care in facilities outside of their community of residence were found to promote retention in care.ConclusionsFeatures of the ART delivery system in the SEARCH intervention and social and structural advantages emerged as facilitators to retention in HIV care among men. Messaging around the health benefits of early ART start, decreasing logistical barriers to HIV care, support of flexible treatment environments, and accelerated linkage to care, are important to men's success in ART treatment programs. Men already benefit from increased social support following disclosure of their HIV-status. Future efforts to shift gender norms towards greater equity are a potential strategy to support high levels of engagement in care for both men and women

Remarkable similarities of chromosomal rearrangements between primary human breast cancers and matched distant metastases as revealed by whole-genome sequencing.

To better understand and characterize chromosomal structural variation during breast cancer progression, we enumerated chromosomal rearrangements for 11 patients by performing low-coverage whole-genome sequencing of 11 primary breast tumors and their 13 matched distant metastases. The tumor genomes harbored a median of 85 (range 18-404) rearrangements per tumor, with a median of 82 (26-310) in primaries compared to 87 (18-404) in distant metastases. Concordance between paired tumors from the same patient was high with a median of 89% of rearrangements shared (range 61-100%), whereas little overlap was found when comparing all possible pairings of tumors from different patients (median 3%). The tumors exhibited diverse genomic patterns of rearrangements: some carried events distributed throughout the genome while others had events mostly within densely clustered chromothripsis-like foci at a few chromosomal locations. Irrespectively, the patterns were highly conserved between the primary tumor and metastases from the same patient. Rearrangements occurred more frequently in genic areas than expected by chance and among the genes affected there was significant enrichment for cancer-associated genes including disruption of TP53, RB1, PTEN, and ESR1, likely contributing to tumor development. Our findings are most consistent with chromosomal rearrangements being early events in breast cancer progression that remain stable during the development from primary tumor to distant metastasis

“Sociedad Ameghiniana de Ciencias Naturales e Instituto de Historia Americana”, un fragmento de historia desconocida de la paleontología argentina del Siglo XX

En esta contribución presentamos sobre el origen, funcionamiento y actividades de la “Sociedad Ameghiniana de Ciencias Naturales e Instituto de Historia Americana” que tuvo su inicio en 1947 y contó con más de 10 años de vida. La sede principal de esta sociedad fue el Museo Escolar de Ciencias Naturales de San Antonio de Areco. Su primera comisión estaba constituida por Carlos Merti (Presidente), Roberto Pertierra (Vice-Presidente), José Mignone y Juan Pisano (Secretarios), Luis Gil Paez (Tesorero), José Bonaparte, Julio Yelpo, Sergio Juanola, Florentino Domingues, Eduardo Soto y Alfredo Rosso (Vocales). Entre los socios se destacan Asencia M. de Ameghino (viuda de Carlos Ameghino), Carlos Rusconi, Galileo Scaglia. La sociedad realizó numerosos eventos en distintas ciudades (e.g., Luján, Mercedes, Chascomús), organizó el “Primer Congreso Ameghiniano de Ciencias Naturales e Historia” en la ciudad uruguaya de Mercedes y el “Congreso Mundial Ameghiniano de Ciencias Naturales” en Luján, y llevó adelante gestiones para la protección del patrimonio paleontológico (e.g., movimiento popular para ésta adquiera la casa de Florentino Ameghino en Luján). Entre las presentaciones científicas en eventos se destacan de entre los otros integrantes de la sociedad las de Lucas Jorge Kraglievich, Osvaldo Reig, Aníbal Montes, Aldo R. J. Paoli y Máximo Valentinuzzi. El lema de la Sociedad fue: “Proseguir la obra de Ameghino estudiando, investigando y ensenando, no pretendiendo más títulos que los del conocimiento, ni más honor que propender a la cultura popular”. A pesar de su dinamismo y de haber contado con la participación de destacados personajes, esta sociedad pasó desapercibida en la historia de la paleontología argentina

Thin films of fluorinated 3d-metal phthalocyanines as chemical sensors of ammonia: an optical spectroscopy study

A comparative study of the sensor response toward gaseous ammonia of hexadecafluorinated 3d-metal phthalocyanine (MPcF16, MCu(II), Co(II), Zn(II), Ni(II)) thin films was performed using complementary experimental (viz., surface plasmon resonance, SPR, and IR absorption spectroscopy) along with theoretical (density functional theory calculations, DFT) techniques. SPR measurements revealed changes of both thickness and optical parameters (refraction indices and extinction coefficients) of the MPcF16 films caused by adsorption of NH3. The MPcF16 species studied exhibited the following order of sensor response: ZnPcF16>CoPcF16≥CuPcF16>NiPcF16. A good correlation was found between the DFT calculated (B3LYP/6-311++G(2df,p)) binding energies, experimentally measured shift of the selected IR bands, and the optical sensor response. Apart from this, we performed a detailed assignment of all intense..

HIV Testing and Treatment with the Use of a Community Health Approach in Rural Africa.

BACKGROUND: Universal antiretroviral therapy (ART) with annual population testing and a multidisease, patient-centered strategy could reduce new human immunodeficiency virus (HIV) infections and improve community health. METHODS: We randomly assigned 32 rural communities in Uganda and Kenya to baseline HIV and multidisease testing and national guideline-restricted ART (control group) or to baseline testing plus annual testing, eligibility for universal ART, and patient-centered care (intervention group). The primary end point was the cumulative incidence of HIV infection at 3 years. Secondary end points included viral suppression, death, tuberculosis, hypertension control, and the change in the annual incidence of HIV infection (which was evaluated in the intervention group only). RESULTS: A total of 150,395 persons were included in the analyses. Population-level viral suppression among 15,399 HIV-infected persons was 42% at baseline and was higher in the intervention group than in the control group at 3 years (79% vs. 68%; relative prevalence, 1.15; 95% confidence interval [CI], 1.11 to 1.20). The annual incidence of HIV infection in the intervention group decreased by 32% over 3 years (from 0.43 to 0.31 cases per 100 person-years; relative rate, 0.68; 95% CI, 0.56 to 0.84). However, the 3-year cumulative incidence (704 incident HIV infections) did not differ significantly between the intervention group and the control group (0.77% and 0.81%, respectively; relative risk, 0.95; 95% CI, 0.77 to 1.17). Among HIV-infected persons, the risk of death by year 3 was 3% in the intervention group and 4% in the control group (0.99 vs. 1.29 deaths per 100 person-years; relative risk, 0.77; 95% CI, 0.64 to 0.93). The risk of HIV-associated tuberculosis or death by year 3 among HIV-infected persons was 4% in the intervention group and 5% in the control group (1.19 vs. 1.50 events per 100 person-years; relative risk, 0.79; 95% CI, 0.67 to 0.94). At 3 years, 47% of adults with hypertension in the intervention group and 37% in the control group had hypertension control (relative prevalence, 1.26; 95% CI, 1.15 to 1.39). CONCLUSIONS: Universal HIV treatment did not result in a significantly lower incidence of HIV infection than standard care, probably owing to the availability of comprehensive baseline HIV testing and the rapid expansion of ART eligibility in the control group. (Funded by the National Institutes of Health and others; SEARCH ClinicalTrials.gov number, NCT01864603.)

Role of SPI-1 Secreted Effectors in Acute Bovine Response to Salmonella enterica Serovar Typhimurium: A Systems Biology Analysis Approach

Salmonella enterica Serovar Typhimurium (S. Typhimurium) causes enterocolitis with diarrhea and polymorphonuclear cell (PMN) influx into the intestinal mucosa in humans and calves. The Salmonella Type III Secretion System (T3SS) encoded at Pathogenicity Island I translocates Salmonella effector proteins SipA, SopA, SopB, SopD, and SopE2 into epithelial cells and is required for induction of diarrhea. These effector proteins act together to induce intestinal fluid secretion and transcription of C-X-C chemokines, recruiting PMNs to the infection site. While individual molecular interactions of the effectors with cultured host cells have been characterized, their combined role in intestinal fluid secretion and inflammation is less understood. We hypothesized that comparison of the bovine intestinal mucosal response to wild type Salmonella and a SipA, SopABDE2 effector mutant relative to uninfected bovine ileum would reveal heretofore unidentified diarrhea-associated host cellular pathways. To determine the coordinated effects of these virulence factors, a bovine ligated ileal loop model was used to measure responses to wild type S. Typhimurium (WT) and a ΔsipA, sopABDE2 mutant (MUT) across 12 hours of infection using a bovine microarray. Data were analyzed using standard microarray analysis and a dynamic Bayesian network modeling approach (DBN). Both analytical methods confirmed increased expression of immune response genes to Salmonella infection and novel gene expression. Gene expression changes mapped to 219 molecular interaction pathways and 1620 gene ontology groups. Bayesian network modeling identified effects of infection on several interrelated signaling pathways including MAPK, Phosphatidylinositol, mTOR, Calcium, Toll-like Receptor, CCR3, Wnt, TGF-β, and Regulation of Actin Cytoskeleton and Apoptosis that were used to model of host-pathogen interactions. Comparison of WT and MUT demonstrated significantly different patterns of host response at early time points of infection (15 minutes, 30 minutes and one hour) within phosphatidylinositol, CCR3, Wnt, and TGF-β signaling pathways and the regulation of actin cytoskeleton pathway